The invention is directed to an electronic thermostat timer having a time-keeping switch means and having a thermostat, having an optoelectronic display means arranged at the front side of the housing for the time of day, the switching times and the switching temperatures, having a manual, key-shaped input means for the time of day, the switching times and the switching temperatures, in a common housing.
In such thermostat timers that can be practically employed not only for a time-controlled temperature regulation of dwelling spaces but also for air conditioning units having heating and/or cooling function, freezer chests, refrigeration rooms and refrigerators, particularly as what are referred to as defroster controls as well, it is necessary--particularly when these are intended to be built-in--that the external dimensions of the overall device be optimally small and compact without the technical demands made of the thermostat being thereby deteriorated. It should thereby be assured that the inertia of such a thermostat is appropriately matched to the respective requirements. As necessary, moreover, what are referred to as optimization functions having up to four temperature levels should be possible, first with a comfort temperature control at 21.degree. C., second with a day time temperature control lowered under chronological control at approximately 19.degree. C., third with a night temperature control lowered under chronological control at approximately 16.degree. C. and, fourth, an antifreezing temperature control at about 5.degree. C., as well as with what is referred to as an automatic surge aeration unit.
It is also required in such thermostat timers that, first, the electrical installation terminals can be placed corresponding to the respective, requirements without the installation orientation of the device having to be changed as a result thereof and that, second, an arrangement of the temperature sensor corresponding to the respective requirements is also possible in addition to a monitoring of the power reserve of the device.
In known electromechanical or electronic thermostat timers, the switch clock and the thermostat are arranged lying spatially side-by-side in a rectangularly fashioned housing that is relatively large in terms of space. The electrical installation terminals are invariably arranged thereat in a specific region of the housing.
These known thermostat timers are relatively large in size and their employment is correspondingly limited.